PIC has been a pain in the arse for me .
The 8-bit PIC is such a brain-dead architecture I'm surprised anyone is still using it. Momentum and stubbornness, I guess.
If you need an 8-bit MCU, AVR is a much better choice. For 16-bit, the MSP430 has a very elegant architecture, and is very low power too. PIC-16 is also nice (it's a totally new architecture and not like its retarded 8-bit brother).
ARM is the way to go with 32-bit as it's supported by just about every MCU company out there with the exception of Microchip. The MIPS-based PIC-32 isn't bad, but it's swimming against the ARM tidal wave. The same with the AVR32. If you do go with ARM, don't go with the older ARM7 architecture -- the newer Cortex-M0 and -M3 series is much easier to use.
Then there are the exotics, which fit well into certain niche applications: the Parallax Propeller and the XMOS. These are both fast, 32-bit multicore MCUs. The XMOS is a blazing fast chip that supports hardware threading, multiple cores, and easy linking of multiple chips together. It's the grandson of the Transputer (both designed by David May) and supports XC (C with parallel extensions), C, and C++ with free Eclipse-based development tools.
The Propeller is very easy for a beginner to use, especially if you're designing the hardware around it. Two drawbacks are that its primary language, Spin, is interpreted and is not C. C is supported, but in a kludgy way.